• NAXJA is having its 18th annual March Membership Drive!!!
    Everyone who joins or renews during March will be entered into a drawing!
    More Information - Join/Renew
  • Welcome to the new NAXJA Forum! If your password does not work, please use "Forgot your password?" link on the log-in page. Please feel free to reach out to [email protected] if we can provide any assistance.

Piston slap: how long?

Quick update to the thread: Added a can of 6-cylinder restore, and as predicted did very little to the one-cyclinder tap. It is a bit quieter especially when hot.

However, and quite surprisingly, it completely got rid of the other cyclinder's lifter tick! How?
 
Restore is totally unique in the world of snake oil additives.

It contains colloidal particles (tiny) of a lead-silver-copper alloy that circulates in the oil and when it hits a hot spot, worn wear area, it melts (the particle melts and plates out onto the hot worn spots) and plates out in that spot repairing scratches and gouges in bearing surfaces. I have studied it and tested it for 10 years, seen it increase compression, increase oil pressure and repair damaged piston cylinder walls first hand.


Quick update to the thread: Added a can of 6-cylinder restore, and as predicted did very little to the one-cyclinder tap. It is a bit quieter especially when hot.

However, and quite surprisingly, it completely got rid of the other cyclinder's lifter tick! How?
 
This is my first post ever, but figured my recent experience was worth chiming in on. I purchased my first XJ (2001 Sport) a few months ago for my son and it sounded a little noisier as compared to my 98 TJ, but since I had never had a day of engine issues with the 98 I just wrote it off as 4.0 normal noise. Well fast forward a few weeks and the noise seemed to get worse so I scoured the forums looking for answers, of which there are plenty, and when I got tired of reading I decided the best first step was to just drop the oil pan and have a look. To my surprise there was a large chunk of the Skirt from the #6 cylinder laying in the bottom. Keep in mind that the XJ was still running and being driven and "seemed" to be just fine albeit noisy. The short answer here is dropping the Oil Pan for an inspection is simple, even for a novice DIY'er and could yield the answer you seek.

I then spent the last few weeks tearing down and rebuilding the 4.0 that only had 160k on the clock and in doing so discovered the #5 Cylinder Skirt was cracked in 2 places as well. Luckily for me the chunk that was broken off did ZERO damage so the rebuild was straight forward. This is the first time I have rebuilt anything larger than a push mower and if you take your time, label everything, take tons of pictures, and use You Tube it really wasn't that difficult. I am about 200 miles into the fresh engine and so far so good. Thanks for reading my long winded post.
 
Replacing worn parts only is what I did. Heck I didn't even remove the engine, but in hindsight I would remove if I ever do one again just to make the rebuild process simpler. I know a lot of guys will moan & groan over the process I chose, but since the engine still ran and showed no other issues I figured what the heck. I replaced the Pistons, Rings, & Rod Bearings with Sealed Power ones from Summit, used a Bottle Brush Hone also from Summit, put in new Lifters from ebay, new Timing Chain/Gear set also from ebay, all new gaskets Fel-Pro only, new Head Bolts Fel-Pro again, and a few other odds and ends. Not sure what I spent since I didn't keep track, but other than the Summit parts I looked for the least expensive options I could find. I hand polished the Crank best I could, cleaned the heck out of everything and then cleaned it again. I re-ground all the valve seats which was a lot simpler than I thought and even though the head was the "dreaded" 0331 version I saw no apparent cracks or cross contamination of oil & coolant so I re-used it. The one thing I did not do myself was putting the new pistons on the rods. For that I found a machine shop and pad about $50 for them to do it which was worth it to me. I cannot stress enough that this is not the preferred way to rebuild an engine, but for my skills/budget it was the best option and so far I am happy with the result and the experience I had in doing it. As far as difficulty level if you are moderately skilled DIY'er and have the space & time to tackle it the job isn't that hard. For me removing/replacing the rear Leaf Springs was more difficult and stressful than rebuilding the engine.
 
Update: Finally got a chance to disable cylinders to see if there was any affect on the noise. From the top of the engine, it's loudest at the very back of the engine near #6. Cold and wet today so I didn't try a stethoscope on the bottom, and as I was working alone I couldn't listen down there while pulling injectors.

All that said, pulling each injector harness had *no* effect on the sound. Am I looking in the right part of the motor?
 
Got some 20w50 in it, and as sort of expected had no effect on the noise. Pretty sure its going to need a rebuild. How long can I ignore this problem before it becomes more serious?

In the event I do get it rebuilt, what all should I have done. I can do research on recommended manufacturers for the various parts, but when I ask a shop I want to know what I should be looking to do for a "proper" rebuild.
 
Have you done a compression test yet?

A spark plug condition inspection on each plug?

And an operating vacuum series of tests with a Vacuum gauge?

Have you physically inspected everything under the valve cover?

Did you pull the valve cover and soak the top of the lifters over night with pure MMO?

You will know a lot more after doing all of these!!! I would do ALL of these before I assumed it might be a bad piston skirt or rod.....

You can pull the head and replace lifters. And inspect everything but the bottom end. You can inspect the bottom end by dropping the oil pan.

I would do those last!!!
 
Good points Mike. I'll do the compression and spark tests. Valve cover and MMO soak I've done. Looked clean as a whistle and the MMO soak didn't work. I'm smelling stronger exhaust though so fearing for the worst.

Have you done a compression test yet?

A spark plug condition inspection on each plug?

And an operating vacuum series of tests with a Vacuum gauge?

Have you physically inspected everything under the valve cover?

Did you pull the valve cover and soak the top of the lifters over night with pure MMO?

You will know a lot more after doing all of these!!! I would do ALL of these before I assumed it might be a bad piston skirt or rod.....

You can pull the head and replace lifters. And inspect everything but the bottom end. You can inspect the bottom end by dropping the oil pan.

I would do those last!!!
 
Back
Top